The present invention relates to a method and apparatus for the frying of potato chips, and other foodstuffs, and especially to such a method and apparatus that is compact and intended for use on demand and in a fast food outlet e.g. in shopping malls, food stores, restaurants, stadiums, amusement parks and the like.
Methods and apparatus for the manufacture of potato chips are known. Such methods usually involve the slicing of the potato and the insertion of the sliced potato into heated oil to effect frying of the potato chip, The potato chip is conveyed through the oil, normally being submerged for at least part of the period of time that the potato chip is in the oil, and then removed from the frying oil. In most instances, the potato chip is packaged in appropriate containers or packages and shipped for subsequent sale to the consumer. Such sale may not occur for several weeks or months.
The methods for the preparation of potato chips include methods in which the temperature of the oil is varied during the process or in which the potato chip is pre-treated prior to being immersed in the frying oil. Examples of such methods include the methods disclosed in U.S. Pat. Nos. 4,366,749, 4,863,750, 4,929,461, 5,137,740 and 5,580,598.
Attempts have been made to produce potato chips on a smaller scale, with the intention that the potato chips would be made available to the consumer shortly after preparation. In particular, attempts have been made to provide freshly made potato chips to the consumer in fast food outlets, using apparatus that is substantially smaller than is used in large scale manufacturing processes for potato chips. Such a method and apparatus is disclosed in U.S. Pat. No. 4,706,556. The method of the patent included heat transfer bars in the bottom of the tank, or kettle, used in the frying to improve efficiency of the process, a potato washing station and variable speed motors for both the potato slicer and the conveyer system so that the speed of the slicer and conveyer could be coordinated with the volume of potato chips being processed. It is understood that, in practice, the apparatus of this patent provided inconsistent product, at least in part due to control mechanisms used in the apparatus.
Apparatus for preparing cooking potato chips is disclosed in U.S. Pat. No. 4,152,975. The apparatus has a conveyor for receiving thin slices cut from a raw potato and conveying the slices along a sinuous path through a heated oil bath. Apparatus in which partially cooked potato slices are re-immersed in cooking oil is described in U.S. Pat. No. 5,193,440. U.S. Pat. No. 3,763,764 describes apparatus for the cooking of taco shells, including means for forming the shells into shape and then cooking the shells. GB Patent 1263923 relates to a process for the treating of yeast products to remove characteristic odours involving contacting yeast material with an edible oil or fat at elevated temperature. U.S. Pat. No. 4,228,730 describes a process for cooking french fried (potato chips) involving conveying frozen potato pieces from a hopper to a bath. A second conveyor submerges the potato pieces during cooking.
U.S. Pat. No. 4,546,684 discloses a potato slicer having a feed tube and an upwardly tapered wall that wedges a potato during slicing. DE 19548209 describes a slicer with a flap for holding vegetables in position during slicing.
Apparatus for preparing potato chips is disclosed in U.S. Pat. No. 3,280,723. The apparatus includes a potato slicer having a potato chute with a smooth inner surface and side walls with a helical contour that converge at the end of the chute. It is stated that the helical walls are arranged so that the curved and narrowing passage leads the potatoes in the direction of rotation of the cutting blade.
An improved method for the manufacture of potato chips so as to provide fresh potato chips to the consumer, especially for use in a fast food outlet, or in other food outlets, is required. Such a method and apparatus has now been found.
Accordingly, one aspect of the present invention provides apparatus for preparing potato chips, said apparatus having a slicer for the slicing of potatoes, means for conveying sliced potatoes through a heated oil bath and for removal of cooked potato chips from the heated oil bath, said slicer comprising a knife blade that rotates at the lower end of a hopper for potatoes, the knife blade being adapted to slice potatoes, the sliced potatoes being fed to the heated bath, the speed of rotation of the knife blade being adapted to be controlled so that the knife blade is stationary when the temperature of the oil bath is below a pre-determined temperature, and the speed of rotation of the knife blade being adapted to be further controlled so that the speed of rotation increases as the temperature is increased above said pre-determined temperature.
A further aspect of the present invention provides a method for the preparation of potato chips in apparatus comprising a slicer for the slicing of potatoes, means for conveying sliced potatoes through a heated oil bath and for removal of cooked potato chips from the heated oil bath, said slicer comprising a knife blade that rotates at the lower end of a hopper for potatoes, the knife blade being adapted to slice potatoes, the sliced potatoes being fed to the heated bath, said method comprising causing the knife blade to be stationary when the temperature of the oil bath is below a pre-determined temperature, rotating the knife blade when said temperature is at or above said pre-determined temperature and increasing the speed of rotation of the knife blade as the temperature is increased above said pre-determined temperature.
A further aspect of the invention provides a slicer for preparing potato chips, comprising:
a rotatable disc having a radial slot therein and a slicing blade projecting above the plane of the disc; and
a chute for downwardly conveying potatoes to said rotatable disc;
an orifice between said chute and said rotatable disc, said orifice having a shape that decreases in depth in the direction of rotation of the rotatable disc.
In a preferred embodiment of the present invention, the orifice is in an ovate shape of decreasing depth in the direction of rotation of the slicing blade.
In a further preferred embodiment of the slicer, the chute is at an acute angle with respect to the direction of rotation of the disc, and in particular terminates in a housing covering and conforming to the said ovate shape.
Another aspect of the invention provides apparatus for the preparing of potato chips, having a potato slicer, a heated oil bath, a conveyor for the conveying of potato slices through the heated oil bath and means for the removal of cooked potato chips from the heated oil bath, in which the slicer for preparing said potato chips comprises (i) a rotatable disc having a radial slot therein and a slicing blade projecting above the plane of the disc; and (ii) a chute for downwardly conveying potatoes to said rotatable disc;
an orifice between said chute and said rotatable disc, said orifice having a shape that decreases in depth in the direction of rotation of the rotatable disc.
In a preferred embodiment of the present invention, the orifice is in an ovate shape of decreasing depth in the direction of rotation of the slicing blade.
Another aspect of the invention provides a method for the preparing of potato chips in apparatus having a potato slicer, a heated oil bath, a conveyor for the conveying of potato slices through the heated oil bath and means for the removal of cooked potato chips from the heated oil bath, in which the slicer for preparing said potato chips comprises (i) a rotatable disc having a radial slot therein and a slicing blade projecting above the plane of the disc; and (ii) a chute for downwardly conveying potatoes to said rotatable disc;
an orifice between said chute and said rotatable disc, said orifice having a shape that decreases in width in the direction of rotation of the rotatable disc;
said method comprising feeding potatoes into the chute of the potato slicer, rotating said disc having the blade extending upwards therefrom by means of which each said potato to be sliced is urged into the narrow end of the tear drop and sliced by said blade, submerging said sliced potato chip in the heated oil bath and removing said potato chip when cooked.
In a preferred embodiment of the present invention, the orifice is in an ovate shape of decreasing width in the direction of rotation of the rotatable disc.
A chute for downwardly conveying potatoes to said rotatable disc;
an orifice between said chute and said rotatable disc, said orifice having a shape that decreases in width in the direction of rotation of the rotatable disc.
In a preferred embodiment of the present invention, the orifice is in an ovate shape of decreasing width in the direction of rotation of the slicing blade.
In another embodiment, the chute has an elbow therein.
Another aspect of the invention provides apparatus for preparing foodstuffs, said apparatus having means for conveying said foodstuffs through a heated oil bath and for removal of cooked foodstuffs from the heated oil bath, said apparatus having a hopper for the foodstuffs and a conveyor belt for feeding foodstuffs to the heated bath, the speed of conveying of the foodstuffs being controlled so that the conveyor is stationary when the temperature of the oil bath is below a pre-determined temperature, and the speed of the conveyor being further controlled so that the speed increases as the temperature is increased above said pre-determined temperature.
A further aspect provides a method for the preparation of foodstuffs in apparatus comprising means for conveying the foodstuffs through a heated oil bath and for removal of cooked foodstuffs from the heated oil bath, said foodstuffs being fed to the heated bath on a conveyor, said method comprising causing the conveyor to be stationary when the temperature of the oil bath is below a pre-determined temperature, and to feed foodstuffs when said temperature is at or above said pre-determined temperature and increasing the speed of conveying the foodstuffs as the temperature is increased above said pre-determined temperature.
In preferred embodiments of the invention, the foodstuffs are corn chips or tortilla chips.